The present invention relates to an image display device, and more particularly to an image display device which is provided with a support body which is interposed between substrates and surrounds a sealed space.
As an image display device which exhibits excellent properties, such as high brightness and high definition, a color cathode ray tube has been conventionally used.
Further, along with the enhancement of the quality of information processing equipment and television broadcasting in recent years, there has been a demand for a panel display which is a lightweight and space-saving image display device that also possessing excellent properties such as high brightness and high definition.
As a typical example, a panel display such as a liquid crystal display device, a plasma display device or the like has been commercialized.
With respect to this type of panel display, as a display device which is capable of exhibiting particularly high brightness, various types of panel displays, such as a field (electron) emission display device and an organic EL display device which is characterized by low power consumption, have been proposed.
Among these panel-type display devices, in a display device, which defines a sealed space between two substrates consisting of a face substrate and a back substrate and sets the pressure inside the sealed space lower than an external atmospheric pressure or evacuates the sealed space, a frame-like support body is arranged to hold a gap between two substrates at a given value and maintains the hermetic property by surrounding the sealed space.
FIG. 8 is a cross-sectional view for explaining one constitutional example of a known field emission image display device. In FIG. 8, the field emission image display device includes a back substrate 1 and a face substrate 2 which faces the back substrate 1 in an opposed manner. Further, a frame-like support body 3 which is constituted of an integral body is interposed between inner peripheral portions of both substrates and is also adhered to the inner peripheral portions of both substrates using a sealing material 4. Further, an inner space which is hermetically defined by both substrates and the support body and constitutes a display region is held at a pressure lower than the external atmospheric pressure or in a vacuum state.
The image display device includes field-emission-type electron sources 5, control electrodes and the like on an inner surface of the back substrate 1. The image display device also includes an anode and a phosphor layer 6 on an inner surface of the face substrate 2. Further, numeral 7 indicates spacers and these spacers 7 are provided for maintaining a distance between both substrates within the above-mentioned display region. These spacers 7 are indispensable these days along with the large-sizing or the increase in size of the display screen.
The back substrate 1 is formed of preferably a material such as glass or ceramic, while the face substrate 2 is formed of a light-transmitting material such as glass. Further, the support body 3 is formed of preferably a material such as glass or ceramics and is fixedly secured to the inner peripheries of the back substrate 1 and the face substrate 2 using the sealing material such as glass frit. The inner space defined by the back substrate 1, the face substrate 2 and the support body 3 is evacuated to create the degree of vacuum of, for example, 10−5 to 10−7 Torr.
Further, the above-mentioned electron sources 5 are constituted of, for example, carbon nanotubes (CNT), diamond-like carbon (DLC) or other field emission cathode.
In such a panel display, with respect to the support body which surrounds the display region while holding the distance between both substrates, there has been known the above-mentioned support body which is integrally formed and a support body which is shown in FIG. 9 as an example in which the support body is formed by joining a plurality of wall members.
FIG. 9 is an explanatory view of a display device which is disclosed in JP-A-2002-298761 and also is a developed perspective view for schematically explaining a constitutional example of a back substrate 1, a face substrate 2 and a support body 3.
In the display device shown in FIG. 9, the back substrate 1 and the face substrate 2 are formed of a glass plate, while the support body 3 is formed of a glass material. Here, various kinds of constitutional parts which are formed on respective inner surfaces of the back substrate 1 and the face substrate 2 are omitted from the drawing.
In FIG. 9, the support body 3 having a given thickness is interposed between peripheries of the back substrate 1 and the face substrate 2 and these members are fixed to each other using a sealing material with a fixed gap between the back substrate 1 and the face substrate 2, thus, forming a sealed space in the inside thereof. The support body 3 is divided into a plurality of wall members 3X1, 3X2, 3Y1, 3Y2 and 3C1 to 3C4.
On respective portions of the respective wall members 3X1, 3X2, 3Y1, 3Y2 and the 3C1 to 3C4 which are arranged close to each other and are also engaged with each other, oblique surfaces 3P are formed. Further, a crossing angle between a normal line which is erected from the oblique surface 3P and a normal line which is erected from the back substrate 1 or the face substrate 2 is set to an acute angle.
Further, FIG. 10A, FIG. 10B and FIG. 10C are views which respectively show a front surface and two side surfaces of the support body shown in FIG. 9, wherein FIG. 10A is a plan view, FIG. 10B is a lateral side view, and FIG. 10C indicates a longitudinal side view.
Numerals in the drawing indicate parts which are identical with the parts shown in FIG. 9.
As shown in FIG. 10A to FIG. 10C, the support body 3 of this example is divided into two long-side wall members 3X1 and 3X2, two short-side wall members 3Y1 and 3Y2, and four corner wall members 3C1, 3C2, 3C3, 3C4, wherein these members are adhered to each other along the respective oblique surfaces 3p thus constituting the support body 3.
Further, JP-A-2000-311630 describes a technique in which a support body includes a first frame member which encloses electron emission elements and a second frame member which encloses the first frame member, these first and second frame members are formed by arranging, positioning and fixing a plurality of plate-like members in a rectangular shape, melting respective contact portions by heating with a burner and, thus, joining the contact portions by welding.
Still further, JP-A-11-317164 discloses a technique on an image forming device having an integral-structure-type support frame, wherein by providing the sealing between a face plate and spacers, between a back plate and the spacers and between the support frame and both of front plate and back plate using glass frit which has different softening points, the number of sealing can be reduced and, hence, the size change can be minimized, whereby the occurrence of minute leaking of liquid crystal can be suppressed.